Polymerizable liquid crystals

Abstract

Disclosed are polymerizable liquid-crystalline compounds of the general formula (I)where A<1 >and A<2 >are identical or different and are each a crosslinkable group; the radicals X are identical or different and are each a single bond, -O-, -S-, -C=N-, -O-CO-, -CO-O-, -O-CO-O-, -CO-NR-, -NR-CO-, -NR-, -O-CO-NR, -NR-CO-O-, -CH2-O- or -NR-CO-NR, in which R is H or C1-C4-alkyl; and M is a mesogenic group, a process for their preparation and their use for preparing cholesteric phases.

We claim:  
     
       1. A polymerizable liquid-crystalline compound of formula (I)                    
       wherein 
       A 1  and A 2  are each independently of one another, a group of the formula  
       
         
           Z—X 1 —(Sp) n — 
         
       
       wherein 
       Z is a crosslinkable radical;  
       X 1  —O—, —S—,—C═N—, —O—CO—, —CO—O—, —O—CO—, —CO—NR—, —NR—CO—, —NR—, —O—CO—NR, —NR—CO—O—, —CH 2 —O— or —NR—CO—NR, in which R is H or C 1 -C 4 -alkyl;  
       Sp is a spacer having from 1 to 30 carbon atoms, in which the carbon chain may be interrupted by either oxygen, thioether sulfur or nonadjacent imino or C 4 -C 1 -alkylimino groups; and  
       n is 0 or 1;  
       the radicals X are identical or different and are each a single bond, —O—, —S—, —C═N—, —O—CO—, —CO—O—, —O—CO—O—, —CO—NR—, —NR—CO—, —NR—, —O—CO—NR, —NR—CO—O—, —CH 2 —O— or —NR—CO—NR, in which R is H or C 1 -C 4 -alkyl; and  
       M is a mesogenic group.  
     
     
       2. The compound as claimed in  claim 1 , wherein A 2  is ortho to A 1  at each occurrence. 
     
     
       3. The compound according to  claim 1 , wherein Sp is: 
       —(CH 2 ) p —, —(CH 2 CH 2 O) m CH 2 CH 2 —, —CH 2 CH 2 SCH 2 CH 2 —, —CH 2 CH 2 NHCH 2  CH 2 —,                    
       wherein 
       m is from 1 to3 and p is from 1 to 12.  
     
     
       4. The compound as claimed in  claim 1 , wherein Z is selected from the group consisting of                    
       —N═C═O, —N═C═S and —O—C≡N,  
       wherein the radicals R are each, independently of one another C 1 -C 4  alkyl.  
     
     
       5. The compound according to  claim 1 , wherein M is selected from groups of the general formula II:                    
       wherein 
       X is as defined above, and  
       Q is substituted or unsubstituted alkylene or a substituted or unsubstituted aromatic bridging group.  
     
     
       6. The compound as claimed in  claim 5 , wherein the aromatic bridging group is selected from the group consisting of                    
       and substituted analogs thereof. 
     
     
       7. A process for preparing a compound as claimed in  claim 1 , which comprises reacting a compound of the formula III                    
       wherein A 1  and A 2  are as defined above and X′ is a reactive side group, with a mesogen compound of the general formula IV 
       
         
           X″—M—X″  (IV)  
         
       
       wherein M is as defined above and X″ is a reactive side group, X′ and X″ being selected such that they are capable of forming group X. 
     
     
       8. The process as claimed in  claim 7 , wherein a mesogen of the formula IV in which X″ is OH is reacted with a compound of the formula III in which X′ is —COOH or —COHal, wherein Hal=F, Cl, Br or I. 
     
     
       9. A composition, comprising: 
       the compound according to  claim 1 , and at least one component selected from the group consisting of a cholesteric group, crosslinkable group, noncrosslinkable group, inorganic pigment, colorant, polymerizable diluent, nonpolymerizable diluent, polymerizable carrier, and nonpolymerizable carrier.  
     
     
       10. A coating composition, comprising: 
       the composition according to  claim 9 .  
     
     
       11. A pigment, comprising: 
       at least one compound according to  claim 1  in a crosslinked form.  
     
     
       12. A coating composition, comprising: 
       the pigment according to  claim 11 .  
     
     
       13. A method for producing an optical element, comprising: 
       contacting the compound according to  claim 1  with the optical element.  
     
     
       14. The method according to  claim 13 , wherein the optical element is a filter or polarizer. 
     
     
       15. A method of producing a multi-layer cholesteric special-effect pigment, comprising: 
       contacting the compound according to  claim 1  with a multi-layer cholesteric special-effect pigment.  
     
     
       16. A method of producing a coating composition, comprising: 
       contacting the compound according to  claim 1  with a coating composition.  
     
     
       17. A method of producing an effect film, comprising: 
       contacting the compound according to  claim 1  with an effect film.  
     
     
       18. A method of producing a cosmetic composition, comprising: 
       contacting the compound according to  claim 1  with a coating cosmetic composition.  
     
     
       19. A method of producing a single layer cholesteric special-effect pigment.